This invention concerns refractories and particularly plastic chrome ore compositions.
Plastic chrome ores are well known in the refractories industry, for example as described in U.S. Pat. Nos. 2,792,311, 2,965,505, and 3,297,458, the disclosures of the later two being incorporated herein by reference.
U.S. Pat. No. 3,297,458 is concerned with solving the problem that some plastic chrome ore refactory compositions bloat or swell under conditions of rapid heating. Specifically, it discloses the addition of floc or asbestos in minor amounts to these compositions to prevent such swelling or bloating.
Although the compositions of U.S. Pat. No. 3,297,458 have proven successful in the marketplace, particularly when they include asbestos, there is some concern that asbestos may pose a health hazard, and accordingly it has been desired to produce a non-bloating plastic chrome ore composition which does not require the use of asbestos.
The present invention is directed to the solution of this problem.